1. Field of the Invention
The present invention relates to a tape cassette for use in a recording and reproducing apparatus such as a video tape recorder (VTR) or a variety of information processing apparatus and, more particularly, to a tape cassette having tape outlets for withdrawing a magnetic tape from a cassette casing in which the tape outlets are exposed and covered by respectively opening and closing lids.
2. Description of the Prior Art
One type of conventional tape cassettes for VTRs comprises a cassette casing having a pair of tape outlets located at opposite ends of a front wall thereof for enabling a magnetic tape contained in the cassette casing to be drawn out. The tape cassette also has a front lid over the front wall which is pivotally supported on the cassette casing for normally covering the tape outlets so as to protect the magnetic tape which may otherwise be damaged by foreign matter brought into contact therewith. When the tape cassette is loaded into a VTR, the front lid of the tape cassette is engaged by a lid opening member in the VTR and, as a result, is turned in an upwardly direction so as to expose the magnetic tape. The VTR has a plurality of tape guides which form a predetermined tape path along which the magnetic tape which is drawn out of the cassette casing runs.
The cassette casing also has a recess located in a lower panel near the front wall and contiguous to the tape outlets. The recess serves as a mouth for receiving a tape loading guide which will be positioned behind the portion of the tape that extends between the tape outlets. The tape loading guide pulls the magnetic tape out of the cassette casing when the tape cassette is loaded into the VTR. The mouth opens in a downwardly direction. As a result, even when the front lid is in a closed position, dust or foreign matter may be applied to the magnetic tape. Similarly, a user's finger may be accidentally inserted so as to touch the magnetic tape, thus applying a fingerprint to the magnetic tape. The dust deposit or fingerprint on the magnetic tape may cause signal dropouts when audio and video information is being recorded on or reproduced from the magnetic tape.
Japanese Laid-Open Patent Publication No. 58-128070 discloses a solution to the above problem. That is, a tape cassette is disclosed which is similar to the conventional tape cassette described above, but also includes an inner lid, located inwardly of the front lid, for normally covering the rear side of the magnetic tape extending between the tape outlets. As a result, when the front lid is closed, the magnetic tape between the tape outlets is effectively sandwiched and sealed between the front and inner lids, so that the magnetic tape is reasonably protected against damage from dust particles or the like. When the tape cassette is inserted into a VTR, the front and inner lids are opened, and a tape loading guide is inserted into the mouth so as to load the magnetic tape along the tape path in the VTR.
More specifically, when the tape cassette is inserted horizontally into the VTR and then moved in a downwardly direction into a cassette loading position, the front lid is turned upwardly by a lid opening member which engages the lower edge of the front lid. At the same time, the inner lid is moved in both an upwardly and a rearwardly direction. Therefore, the front and inner lids are opened or moved away from the magnetic tape, thereby opening the tape outlets and the mouth so as to allow the magnetic tape to be loaded along the tape path.
The tape cassettes of the type described above have tape guides disposed within the cassette casing. When the magnetic tape is running, it is in sliding contact with these tape guide. Thus, the accuracy of the tape path is affected by the tape guides. FIGS. 1A and 1B show a conventional tape cassette which is designed to alleviate such a drawback.
As shown in FIGS. 1A and 1B, the tape cassette comprises a cassette casing 1a having a pair of wide tape outlets 6, 7 located at opposite ends of a front wall for enabling a magnetic tape T to be drawn out of the cassette casing la. When the tape cassette is loaded into a VTR, the magnetic tape T is drawn out of the cassette casing 1a through the tape outlets 6, 7 and loaded along a tape path in the VTR by a pair of tape loading guides 32, 33 which move in an angular direction and are respectively located near the tape outlets 6, 7. As the diameter of the magnetic tape T of tape reels 4, 5 varies between a maximum diameter R and a minimum diameter r, the magnetic tape T is held out of contact of the cassette casing 1a and inner walls
thereof, by tape guides 16a, 16b, respectively and respectively traverses triangular areas As, At at the tape outlets 6, 7. In the structure shown in FIGS. 1A and 1B, the tape path has reduced accuracy.
Abutment surfaces 1a1, 1a2 are located at opposite ends of the front wall. These abutment surfaces 1a1, 1a2 are substantially identical to those of the existing VHS-format type tape cassettes.
The tape cassette of FIGS. 1A and 1B also has a recess 8 located between and contiguous to the tape outlets 6, 7, and serves as a mouth for receiving the tape loading guides 32, 33 for loading the magnetic tape T.
In tape cassettes having front and inner lids, when the front and inner lids are to be opened, the inner lid cannot normally be moved away from the magnetic tape unless the front lid is rotated through an angle which is greater than that through which front lids of tape cassettes without inner lids are rotated. As a result, the lid opening member for engaging and rotating or turning the front lid for tape cassettes having front and inner lids is larger in height than that associated with tape cassettes without inner lids.
For this reason, the tape cassette having both front and inner lids cannot normally be used in VTRs designed for use with general type tape cassettes which do not have inner lids. In other words, tape cassettes having only front lids and tape cassettes having both front and inner lids may not be used interchangeably in conventional VTRs.
In FIGS. 1A and 1B, the wide tape outlets 6, 7 allow the magnetic tape T to respectively traverse the triangular areas As, At while the magnetic tape is being drawn out of the cassette casing 1a and guided by the tape loading guides 32, 33 so as to follow the tape path. The front wall of the cassette casing has a recess 21, located adjacent to and outwardly of the tape outlet 7, which is positioned near the tape reel 5 which, for example, may be a takeup reel. The recess 21 serves to receive the lid opening member for opening the front lid of the tape cassette. The triangular area At, at the tape outlet 7, is shaped so as to point inwardly in order to prevent the magnetic tape T from contacting the inner wall portion of the recess 21 which projects into the cassette casing.
The tape path is thus required to be located inwardly of the arrow shown in FIG. 1A. Such a requirement imposes a limitation which causes effective utilization of the deck surface in the VTR not to be achieved. To avoid the above shortcoming, a guide post P may be added in front of the tape outlet 7, as shown in FIG. 1B, so as to direct the magnetic tape T outwardly. However, since the coated magnetic layer of the magnetic tape T is in sliding contact with the guide post P, the magnetic tape T may be damaged by the guide post P.